We've distilled this into a reproducible environment with a stack of NFS + XFS
to a local disk + automated sysrq 'b' reboots. We're working on getting
this bundled up into a nice little package as a VirtualBox vm for your
consumption. Please tell me if this is not desirable.

The self-contained and reproducible environment can be downloaded from the
following location:
http://www.jquigley.com/tmp/xfsVM.tar.bz2
That's a ~550 MB (compressed) image that can be 'imported' directly into the
latest VirtualBox. Instructions for setting up the environment (trivial,
should take you a mere couple of minutes):
http://www.jquigley.com/tmp/README.txt
The basic concept here is to use the VM as the file server, accessing the XFS
file system thereon through the guest OS which acts as the NFS client.
Automated reboots are effected with cron and sysrq 'b', so you can just set
this up and run it until failure.
Hope this helps lend insight - if there are any questions, please ask. Thanks
for your time.
- John Quigley